If this is really given, find peace and connect yourself more to the other-world. If you haven't already, you should achieve astral projection and leave behind physical affairs and things that connects you here so strongly, so that the transition is smooth. Complete stuff you must, and be done with this life.
As for spiritual work, this is individual, but I would personally engrave into my soul that I'm always with Satan and the Gods and I always striving to be perfect. I would free my soul from things that was really influencing me bad in this life. And would go full on advancing my soul, "not living in the physical anymore" only for the necessary stuff. But as I said, this is only if I'm completely sure that I'm about to die. I would also ask the Gods to grace me a peaceful death, and to ensure a smooth transition.